Reciprocating compressor

ABSTRACT

A reciprocating compressor includes: a reciprocating motor installed in the container and having an outer stator and an inner stator provided with at least one step portion at both sides thereof, and an armature linearly moving therebetween; a compression unit having a cylinder and a piston inserted in the cylinder to receive a linear and reciprocal driving force of the reciprocating motor and compress a gas while making a linear and reciprocal movement; a suction unit sucking a gas sucked into the container through the gas suction pipe due to a pressure difference in the compression unit, into the compression unit; a discharge unit discharging the gas compressed in the compression unit to outside the container; a resonance spring unit elastically supporting the piston and the armature; and a frame unit supporting the compression unit and the reciprocating motor. Since the stable driving is made in its operating, generation of a vibration and a noise can be minimized, heightening a reliability. In addition, since the gas discharge amount according to the stroke control can be accurately controlled, an unnecessary loss can be reduced.

TECHNICAL FIELD

[0001] The present invention relates to a reciprocating compressor thatis capable of minimizing a vibration noise occurring in operation,accurately controlling the amount of a compressed gas to be discharged,simplifying assembly of a construction components, and minimizing theassembly tolerance.

BACKGROUND ART

[0002] In general, a compressor is an instrument to compress a gas suchas a coolant. There are several types of compressors including a rotarycompressor, a reciprocating compressor, a scroll compressor.

[0003] The general compressor includes a closed container having a spacetherein, an electronic mechanism unit installed inside the closedcontainer and generating a driving force, and a compression mechanismunit for receiving the driving force from the electronic mechanism unitand compressing gas.

[0004]FIG. 1 is a sectional view of the rotary compressor in accordancewith a conventional art.

[0005] As shown in FIG. 1, in the rotary compressor, as a rotor 2 of anelectronic mechanism unit (M) installed in a closed container 1 isrotated, a rotational shaft 3 press-fit in the rotor 2 is rotated.According to the rotation of the rotational shaft 3, a rolling piston 5inserted in an eccentric part 3 a of the rotational shaft 3 positionedin the compression space (P) of a cylinder 4 linearly contacts the innercircumferential surface of the compression space (P) of the cylinder andalso linearly contacts a vane (not shown) inserted at one side of thecylinder 4 to divide the compression space (P) into a high pressureportion and a low pressure portion, so as to be rotated in the cylindercompression space (P) to compress a coolant gas sucked into a suctionhole 4 a formed at the cylinder 4 and discharge it through a dischargepassage 4 b. These processes are repeatedly performed.

[0006]FIG. 2 is a sectional view of a reciprocating compressor inaccordance with a conventional art.

[0007] As shown in FIG. 2, in the reciprocating compressor, as a rotor12 of an electronic mechanism unit (M) mounted in a closed container 11is rotated, a crank shaft 13 press-fit to the rotor 12 is rotated.According to the rotation of the crank shaft 13, a piston 14 coupled toan eccentric part 13 a of the crank shaft 13 makes a linear andreciprocal movement in the compression space (P) of the cylinder 15, tocompress a coolant gas sucked through a valve assembly 16 coupled to thecylinder 15 and discharge the coolant gas through the valve assembly 16.These processes are repeatedly performed.

[0008]FIG. 3 is a sectional view of a scroll compressor in accordancewith a conventional art.

[0009] As shown in FIG. 3, in the scroll compressor, as a rotor 22 ofthe electronic mechanism unit (M) mounted in the closed container 21 isrotated, a rotational shaft 23 having an eccentric part 23 a press-fitto the rotor 22 is rotated. According to the rotation of the rotationalshaft 23, an orbital scroll 24 connected to the eccentric part 23 a ofthe rotational shaft 23 is engaged with a fixed scroll 25 and revolved.Then, a plurality of compression pockets formed by wraps 24 a and 25 ahaving an involute curved line form respectively formed at the orbitalscroll 24 and the fixed scroll 25 are reduced in size, to suck, compressand discharge a coolant gas continuously. This processes are repeatedlyperformed.

[0010] The structural and reliability aspects of the rotary compressor,the reciprocating compressor and the scroll compressor of theconventional art each operated in a compression mechanism as describedabove will now be described.

[0011] First, referring to the rotary compressor, in the structuralaspect, since a plurality of balance weights 6 are used coupled to therotor 2 to rotational balance between the rotational shaft 3 having theeccentric part 3 a, the rolling piston 5 press-fit to the eccentric part3 a and the eccentric part 3 a, there are many constructional componentsand its structure is somewhat complicated. In the aspect of areliability, since the eccentric part 3 a and the rolling piston 5formed at the rotational shaft 3 are eccentrically rotated, a bigvibration noise is generated.

[0012] Referring to the reciprocating compressor, in its structuralaspect, the balance weight 13 b is used for a rotational balance betweenthe crank shaft 13 having an eccentric part 13 a, the piston 14 coupledto the crank shaft 13 and the crank shaft eccentric part 13 a, resultingin that there are numerous components and its structure is complicated.

[0013] In addition, in the aspect of a reliability, since the eccentricpart 13 a formed at the crank shaft 13 is eccentrically rotated, avibration noise is generated, and since the valve assembly 16 isoperated in sucking and discharging, the noise in sucking anddischarging is made big.

[0014] Referring to the scroll compressor, in the aspect of itsstructural aspect, the balance weight 26 is used for a rotationalbalance between the rotational shaft 23 having the eccentric part 23 a,the orbital scroll 24 having a wrap formed in an involute curve form,the fixed scroll 25 and the eccentric part 23 a, resulting in that thereare many components and its structure is complicated. In addition, it isdifficult to process the orbital scroll 24 and the fixed scroll 25.

[0015] In addition, in the aspect of reliability, a vibration noise isgenerated due to the turning movement of the orbital scroll 24 and theeccentric movement in the eccentric part 23 a of the rotational shaft.

[0016] As stated above, in case of the rotary compressor, thereciprocating compressor and the scroll compressor, the compressionmechanism unit compresses a gas upon receipt of a rotational force ofthe electronic mechanism unit. Thus, in order to control the amount ofthe compressed gas generated in the compressor, the number of rotationsof the electronic mechanism unit should be reduced or the electronicmechanism unit should stop rotating, which makes it difficult toaccurately control the amount of the compressed gas.

[0017] In addition, since the eccentric parts 3 a, 13 a and 23 a areprovided at the shaft which is rotated upon receipt of the rotationalforce from the electronic mechanism unit, the balance weights 6, 13 band 26 are used, causing that a driving force is much consumed, and asthe vibration noise is generated in operation, its reliability isdegraded. In addition, since the structure is relatively complicate, theassembly productivity is degraded.

DISCLOSURE OF THE INVENTION

[0018] Therefore, it is an object of the present invention to provide areciprocating compressor that is capable of accurately controlling theamount of a compressed gas to be discharged as well as minimizing avibration noise generated in operation.

[0019] Another object of the present invention is to provide areciprocating compressor that is capable of simplifying assembly ofcomponents and minimizing an assembly tolerance.

[0020] To achieve these objects, there is provided a reciprocatingcompressor including: a container communicating with a gas suction pipefor sucking a gas; a reciprocating motor installed in the container andhaving an outer stator and an inner stator provided with at least onestep portion at both sides thereof, and an armature linearly movingtherebetween; a compression unit having a cylinder and a piston insertedin the cylinder to receive a linear and reciprocal driving force of thereciprocating motor and compress a gas while making a linear andreciprocal movement; a suction unit sucking a gas sucked into thecontainer through the gas suction pipe due to a pressure difference inthe compression unit, into the compression unit; a discharge unitdischarging the gas compressed in the compression unit to outside thecontainer; a resonance spring unit elastically supporting the piston andthe armature; and a frame unit supporting the compression unit and thereciprocating motor and having a front frame which supports thereciprocating motor at the front side and a rear frame which supportsthe reciprocating motor at the rear side, one of the front and the rearframe having at least two step portions for supporting both outer statorand inner stator of the reciprocating motor, the front frame and therear frame having at least one step portion of which circumferentialface forms a concentric circle with the inner diameter of the cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIG. 1 is a sectional view showing a rotary compressor inaccordance with a conventional art;

[0022]FIG. 2 is a sectional view showing a reciprocating compressor inaccordance with a conventional art;

[0023]FIG. 3 is a sectional view showing a scroll compressor inaccordance with a conventional art;

[0024]FIG. 4 is a sectional view showing a reciprocating compressor inaccordance with a first embodiment of the present invention;

[0025]FIG. 5 is a partial sectional view showing a mass member of thereciprocating compressor in accordance with the first embodiment of thepresent invention;

[0026]FIG. 6 is a schematic view showing a bolt engaging part of thereciprocating compressor in accordance with the first embodiment of thepresent invention;

[0027]FIG. 7 is a schematic view showing a support spring and acombining protrusion in accordance with the first embodiment of thepresent invention;

[0028]FIG. 8 is a schematic view showing a power supply terminal and afixing terminal of a first connector and a second connector inaccordance with the first embodiment of the present invention;

[0029]FIG. 9 is a front view showing the second connector in accordancewith the first embodiment of the present invention;

[0030]FIG. 10 is a sectional view showing a reciprocating compressor inaccordance with a second embodiment of the present invention;

[0031]FIG. 11 is a schematic view showing a position of a resonancespring support of the reciprocating compressor in accordance with thesecond embodiment of the present invention;

[0032]FIG. 12 is a partial sectional view showing a windage lossreducing through hole of the reciprocating compressor in accordance withthe second embodiment of the present invention;

[0033]FIG. 13 is a partial sectional view showing a support protrusionand an insertion recess formed at the spring support of thereciprocating compressor in accordance with the second embodiment of thepresent invention;

[0034]FIG. 14 is a partial sectional view showing a construction of aninitial position control member of the reciprocating compressor inaccordance with the second embodiment of the present invention; and

[0035]FIG. 15 is a schematic view showing a bolt engaging part of thereciprocating compressor in accordance with the second embodiment of thepresent invention.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

[0036] The reciprocating compressor of the present invention will now bedescribed with reference to the accompanying drawings.

[0037]FIG. 4 is a sectional view showing a reciprocating compressor inaccordance with a first embodiment of the present invention.

[0038] As shown in FIG. 4, the reciprocating compressor includes acontainer 100 communicating with a gas suction pipe 110 for sucking agas, a reciprocating motor 200 installed in the container 100, forgenerating a linear reciprocal driving force; a compression unit 300positioned inside the reciprocating motor 200, for receiving the linearreciprocal driving force of the reciprocating motor 200 and compressinga gas; a suction unit 400 positioned at one side of the compression unit300, for rendering the gas sucked into the container 100 through the gassuction pipe 110 due to the pressure difference in the compression unit300 to be sucked into the compression unit 300; a discharge unit 500positioned at the other side of the compression unit 300, fordischarging the gas compressed in the compression unit 300 to theoutside of the container 100; a resonance spring unit 600 constructingthe compression unit 300, for elastically supporting the piston whichmakes a reciprocal movement linearly upon receipt of the linearreciprocal driving force of the reciprocating motor 200; a frame unit700 at which the reciprocating motor 200 and the compression unit 300are mounted; and a support spring 800 elastically supporting the frameunit 700 at the container 100.

[0039] The frame unit 700 includes a front frame 710, a middle supportmember 720 and a rear frame 730. The front frame 710 includes a cylinderinsertion hole 712 formed at the middle of body part 711 of apredetermined form, a first step portion 713 formed at a marginalportion of one side of the body part 711 and a second step portion 714formed at the middle portion of one side of the body part 711.

[0040] The first step portion 713 and the second step portion 714 of thefront frame have a circumferential faces a1 and a2 having apredetermined width and a vertical faces b1 and b2 (in the drawing)formed vertical to the circumferential faces a1 and a2. Thecircumferential face a1 of the first step portion 713 and thecircumferential face a2 of the second step portion 714 are formed tomake a concentric circle.

[0041] The reciprocating motor 200 includes an outer stator 210, aninner stator 220 and an armature 230.

[0042] The outer stator 210 is provided to be cylindrical form in whicha winding coil 240 is combined, and step portions 211 and 212 are formedat both sides thereof.

[0043] The step portion 211 of the outer stator 210 is insertedlycombined into the first step portion 713 of the front frame.

[0044] At this time, a circumferential face d1 and a vertical face e1(in the drawing) forming the step portion 211 of the outer stator andthe circumferential face a1 and the vertical face b1 forming the firststep portion 713 of the front frame supportedly contact each other.

[0045] The inner stator 220 has a cylindrical form with a predeterminedthickness, of which a step portion 221 forming an inner corner isinsertedly combined into the second step portion 714 of the front frame

[0046] At this time, the inner stator 220 is positioned with apredetermined interval at the inner side of the outer stator 210, and acircumferential face f1 and a vertical face g1 (in the drawing) formingthe step portion 221 of the inner stator and the circumferential face a2and the vertical face b2 forming the second step portion 714 of thefront frame supportedly contact each other.

[0047] The armature 230 includes a magnet holder 231 having acylindrical form and a permanent magnet 232 coupled to the outercircumferential surface of the magnet holder 231. The armature 230 isinserted between the outer stator 210 and the inner stator 220.

[0048] The compression unit 300 includes a cylinder 310 and a piston320.

[0049] The cylinder 310 is inserted into the cylinder insertion hole 712of the front frame 710 and positioned inside the inner stator 220 of thereciprocating motor 200.

[0050] At this time, the inner diameter of the cylinder 310 and thecircumferential faces a1 and a2 of the first and the second stepportions 713 and 714 make the concentric circle.

[0051] The piston 320 includes a flange 322 extended and bent to have apredetermined area at one side of the body part 321 having a annular barform with a predetermined length in which a gas flowing passage (F) isformed in the longitudinal direction.

[0052] The body part 321 of the piston 320 is inserted into the cylinder310 and the flange 322 is coupled to the armature 230.

[0053] An annular groove 311 having a predetermined width and depth isformed on the inner wall of the cylinder 310 of the compression unit300. The distance between the groove 311 and the front end (left side inFigure) of the cylinder 310 is longer than the distance between thegroove 311 and the rear end of the cylinder 310.

[0054] The groove 311 of the cylinder is preferably formed to bepositioned roughly at the middle portion of the overall length of thepiston 320 when the piston 320 comes to the bottom dead point.

[0055] At least one lubricant through hole 312 is provided within thegroove 311 of the cylinder, having the smaller inner diameter than thewidth of the groove 311.

[0056] It is preferred that the lubricant through hole 312 is formedboth at the upper and the lower portions, so as to be positioned in thevertical line on the basis of the lubricant face.

[0057] The middle support member 720 of the frame unit 700 includes afirst step portion 722 formed at one side of the annular body 721 havinga predetermined thickness and width and a second step portion 723 formedat the other side thereof.

[0058] A circumferential face h1 forming the first step portion 722 anda circumferential face h2 forming the second step portion 723 make theconcentric circle, and the outer circumferential face of the annularbody 721 and the circumferential face h1 forming the first step portion722 make the concentric circle. The inner diameter of the annular body721 is larger than the inner diameter of the outer stator of thereciprocating motor 200.

[0059] The middle support member 720 is insertedly coupled to the stepportion 212 of the outer stator of the reciprocating motor 200. At thistime, the circumferential face h1 and the vertical face k1 (in thedrawing) forming the first step portion 722 of the middle support memberand a circumferential face d2 and a vertical face e2 forming the stepportion 212 of the outer stator supportedly contact each other.

[0060] The rear frame of the frame unit 700, formed in a cap form,includes a step portion 732 formed at one side and a through hole 732formed at the other side thereof.

[0061] The rear frame 730 is insertedly coupled to the second stepportion 723 of the middle support member. At this time, acircumferential face m1 and a vertical face (in the drawing) forming thestep portion 731 of the rear frame and a circumferential face h2 and avertical face k2 forming the second step portion 723 supportedly contacteach other, and the through hole 732 of the rear frame is positionedadjacent to the gas suction pipe 110.

[0062] The frame unit 700 includes an inner support member 740 which hasa cylindrical body 741 having a predetermined diameter and length, asupport 742 bent extended to have a predetermined area at one side ofthe cylindrical body 741 and a stopper 743 bent extended to have apredetermined area at the other side thereof.

[0063] The support 742 and the cylindrical body 741 of the inner supportmember 740 are inserted between the outer circumferential surface of thecylinder 310 and the inner circumferential surface of the inner stator220, so as to be integrally combined with the inner stator 220 bywelding or bolting.

[0064] At this time, the support 742 supportedly contacts the front endof the front frame 710 and the stopper 743 is supported by one side faceof the inner stator 220.

[0065] The cylindrical body 741 of the inner support member and thecircumferential faces h1 and h2 of the first and the second stepportions 722 and 723 of the middle support member make concentriccircle.

[0066] The resonance spring unit 600 includes two coil springs, one ofwhich is coupled between the support 742 of the inner support member andthe flange 322 of the piston and the other is coupled between the flange322 of the piston and the inner side face of the rear frame 730.

[0067] A spring base 610 of a predetermined form is inserted betweencomponents which contact the coil spring.

[0068] The piston 320 which makes a reciprocal movement linearly uponreceipt of the driving force of the reciprocating motor 200 and thecombining part to which the armature 230 of the reciprocating motor 200is combined is preferably formed in a manner that the flange 322 of thepiston, the plastic armature 230, that is, the magnet holder 231 made ofplastic, and the spring base 610 supporting the resonance spring unit600 are sequentially arranged to be engaged.

[0069] That is, as they are engaged in the order of metal-plastic-metal,the armature made of plastic is prevented from deforming or damaging,helping maintain the rigidity of the engaging structure.

[0070]FIG. 5 is a partial sectional view showing a mass member of thereciprocating compressor in accordance with the first embodiment of thepresent invention.

[0071] As shown in FIG. 5, a mass member 900 is provided between themagnet holder 231 constructing the armature 230 of the reciprocatingmotor and the flange 322 of the piston 320 to which the magnet holder231 is combined. The mass member 900 preferably has a disk form having apredetermined thickness.

[0072] Thanks to the attachment of the mass member 900, the resonancefrequency of the moving mass constructed by including the piston 320which makes a reciprocal movement linearly together with the armature230 of the reciprocating motor 200 upon receipt of the linear reciprocalmovement of the armature 230 and the resonance spring unit 600supporting the piston 320 can be accurately controlled.

[0073] Accordingly, since the resonance frequency of the moving part ofthe reciprocating motor 200 can be roughly conformed to the frequency ofthe power source supplied to the reciprocating motor 200, the stroke ofthe reciprocating motor can be more accurately controlled.

[0074] The suction unit 400 includes a gas flowing passage (F) formedinside the body part 321 of the piston 320 and a suction valve 410coupled to the front end of the piston 320, for opening and closing thegas flowing passage (F) according to the pressure difference.

[0075] The discharge unit 500 includes a discharge cover 510 combined tocover the cylinder 310, that is, the compression space (P), a dischargevalve 520 positioned inside the discharge cover 510, for opening andclosing the compression space (P) of the cylinder 310, and a valvespring 530 for elastically supporting the discharge valve 520.

[0076] The front frame 710 and the middle support member 720 supportingthe both sides of the reciprocating motor 200 is engaged by a pluralityof engaging bolts and nuts each having a predetermined length.

[0077]FIG. 6 is a schematic view showing a bolt engaging part of thereciprocating compressor in accordance with the first embodiment of thepresent invention.

[0078] As shown in FIG. 6, the bolt engaging portion 715 is extendedlyprotruded in a semi-circle form at the marginal portion of the body part711 of the front frame, in which a screw hole is formed.

[0079] The bolt engaging portions 715 are disposed at the upper and thelower sides on the basis of a horizontal line when the front frame 710is vertically positioned, and the bolt engaging portions 715 arepositioned at the left and the right sides on the basis of the centralvertical line of the front frame 710.

[0080] The bolt engaging portions of the middle support member 720,which is engaged along with the front frame 710 are disposed in the sameform.

[0081] A fillet portion (C) is formed at the corner portions of thefront frame 710, the rear frame 730 and the middle support member 720constructing the frame unit 700.

[0082] The fillet portion (C) includes a relatively large portion and arelatively small portion to reduce the outer size of the compressor.

[0083] The fillet (C) may be modified to a flat form chamfer.

[0084] Since the front frame 710 constructing the frame unit 700 and thebolt engaging portion 715 engaging the middle support member 720 arepositioned between the vertical line and the horizontal line rather thanbeing positioned on the central vertical line and the horizontal line ofthe front frame 710 and the middle support member 720, and the fillet(C) is provided at the corner of the frame unit 700, the frame unit 700is prevented from contacting the inner face of the container 100 and thedistance to the inner face is minimized. Thus, its structure is compact.

[0085] The support spring 800 includes a plurality of coil springs. Oneside of the support spring 800 is fixedly supported at the bottom of thecontainer 100 and the other side thereof is fixedly supported by theframe unit 700.

[0086]FIG. 7 is a schematic view showing a support spring and acombining protrusion in accordance with the first embodiment of thepresent invention.

[0087] As shown in FIG. 7, in the structure in which the support spring800 and the frame unit 700 are fixedly supported, a combining protrusion910 is provided to be integrally formed at one side of the frame unit700.

[0088] A combing recess 911 is formed with a predetermined depth at acontact line where the outer circumference of the combining protrusion910 and the frame unit 700 meet.

[0089] The combining protrusion 910 is inserted to be fixedly combinedinto one side of the support spring 800.

[0090]FIG. 8 is a schematic view showing a power supply terminal and afixing terminal of a first connector and a second connector inaccordance with the first embodiment of the present invention, and FIG.9 is a front view showing the second connector in accordance with thefirst embodiment of the present invention.

[0091] As shown in FIGS. 8 and 9, a first connector 120 having two powersupply terminals 121 to which an external power is supplied and at leastone fixing terminal 122 is formed penetrating the container 100.

[0092] A second connector 920 is provided having two power supplyterminal 921 connected to the power supply terminal 121 of the firstconnector 120 and withdrawn from the reciprocating motor 200 to supply apower to the reciprocating motor 200 and a fixing terminal 922insertedly combined with the fixing terminal 122 of the first connector.

[0093] When the first connector 120 and the second connector 920 arecombined with each other, the power supply terminal 121 of the firstconnector 120 and the power supply terminal 921 of the second connector920 are combined, and at the same time, the fixing terminal 122 of thefirst connector 120 and the fixing terminal 922 of the second connector920 are insertedly combined with each other.

[0094] As the power supply terminal 121 of the first connector and thepower supply terminal 921 of the second connector 920 are connected toeach other, an external power is supplied to the reciprocating motor200, and as the fixing terminal 122 of the first connector 120 and thefixing terminal 922 of the second connector 920 are combined to eachother, the first and the second connectors 120 and 920 are firmlycombined and maintained.

[0095] The operational effect of the reciprocating compressorconstructed as described above will now be explained.

[0096] When a power is supplied to the reciprocating motor 200, acurrent flows to the winding coil 240 which constructs the reciprocatingmotor 200, and accordingly, a flux is generated at the outer stator 210and the inner stator 220. The interaction of the flux generated at theouter stator 210 and the inner stator 220 and the flux according to thepermanent magnet 232 of the armature 230 renders the armature 230 toundergo a linear reciprocating movement .

[0097] The linear and reciprocal driving force of the armature 230 istransmitted to the piston 320, and then, the piston 320 is linearly andreciprocally moved in the compression space (P) of the cylinder.

[0098] At this time, the resonance spring unit 600 stores the linear andreciprocal movement force of the reciprocating motor 200 as an elasticenergy and discharges it and induces a resonance movement.

[0099] Due to the pressure difference caused when the piston 320 islinearly and reciprocally moved in the compression space (P) of thecylinder 310, the gas sucked into the gas suction pipe 110 is suckedinto the compression space (P) of the cylinder of the compression unit300 through the suction unit 400, compressed therein and dischargedthrough the discharge unit 500.

[0100] The high temperature and high pressure gas discharged through thedischarge unit 500 is discharged through the discharge pipe 111 tooutside the container 100.

[0101] In the reciprocating compressor of the first embodiment of thepresent invention, since the piston 320 is linearly and reciprocallymoved in the cylinder 310 upon receipt of the linear and reciprocaldriving force of the reciprocating motor 200, to compress the gas, itsdriving is stably made.

[0102] In addition, since the stroke of the piston 320 can be controlledby controlling the linear movement distance of the reciprocating motor200, the amount of the compressed gas to be discharged can be accuratelycontrolled.

[0103] The step portion 211 of the outer stator 210 which constructs thereciprocating motor 200 supportedly contacts to be combined with thefirst step portion 713 of the front frame 710 which constructs the frameunit 700, and the step portion 221 of the inner stator 220 of thereciprocating motor supportedly contacts to be combined with the secondstep portion 714 of the front frame 710, so that the concentricity ofthe outer stator 210 and the inner stator 220 can be accurately adjustedand the interval therebetween can be constantly maintained.

[0104] In addition, the first step portion 722 of the middle supportmember 720 of the frame unit 700 supportedly contacts to be combinedwith the other step portion 212 of the outer stator 210 of thereciprocating motor, so that the assembly firmness can be increased.

[0105] Moreover, since the front frame 710 of the frame unit 700supports both the outer stator 210 and the inner stator 220 of thereciprocating motor 200 and the middle support member 720 supports onlythe outer stator 210, a leakage of flux formed at the outer stator 210and the inner stator 220 can be reduced.

[0106]FIG. 10 is a sectional view showing a reciprocating compressor inaccordance with a second embodiment of the present invention, in which acompression unit 300 and a reciprocating motor 200 are positioned with apredetermined interval therebetween.

[0107] The reciprocal compressor in accordance with the secondembodiment of the present invention includes a container 100 providedwith a gas suction pipe 110 through which a gas is sucked; a frame unit700 installed inside the container 100, a reciprocating motor 200mounted at the frame unit 700, for generating a linear and reciprocaldriving force; a compression unit 300 mounted at the frame unit 700 at apredetermined interval from the reciprocating motor 200, for receivingthe driving force of the reciprocating motor 200 and compressing a gas;a resonance spring unit 600 for elastically supporting the linear andreciprocal driving force of the reciprocating motor 200; a suction unit400 positioned at one side of the compression unit 300, for renderingthe gas sucked into the container 100 through the gas suction pipe 110due to the pressure difference by he compression unit 300 to be suckedinto the compression unit 300; a discharge unit 500 positioned at theother side of the compression unit 300, for discharging the gascompressed in the compression unit 300 to the outside of the container100; and a support spring 800 elastically supporting the frame unit 700at the container 100.

[0108] The frame unit 700 includes a front frame 750, a middle supportmember 760 and a rear frame 770. The rear frame 770 includes a body part771 having a circle form and a predetermined thickness, a through hole772 formed at the central portion of the body part 771, a first stepportion 773 formed at the marginal portion of the body part 771 and asecond step portion 774 formed at the middle of the body part 771.

[0109] The first step portion 773 and the second step portion 774 hascircumferential faces a3 and a4 with a predetermined width and verticalfaces b3 and b4 (in the drawing) formed vertical to the circumferentialfaces a3 and a4.

[0110] The circumferential face a3 of the first step portion 773 and thecircumferential face a4 of the second step portion 774 make a concentriccircle to each other.

[0111] The through hole 772 of the rear frame 770 is positioned adjacentto the gas suction pipe 110.

[0112] The reciprocating motor 200 includes the outer stator 210 and theinner stator 220 and the armature 230.

[0113] The reciprocating motor 200 includes an outer stator 210, aninner stator 220 and an armature 230.

[0114] The outer stator 210 is provided to be cylindrical form in whicha winding coil 240 is combined, and step portions 211 and 212 are formedat both sides thereof.

[0115] The step portion 211 of the outer stator 210 is insertedlycombined into the first step portion 773 of the rear frame 770.

[0116] At this time, a circumferential face d1 and a vertical face e1(in the drawing) forming the step portion 211 of the outer stator andthe circumferential face a3 and the vertical face b3 forming the firststep portion 713 of the front frame supportedly contact each other.

[0117] The inner stator 220 has a cylindrical form with a predeterminedthickness, of which a step portion 221 forming an inner corner isinsertedly combined into the second step portion 774 of the rear frame770.

[0118] At this time, the inner stator 220 is positioned with apredetermined interval at the inner side of the outer stator 210, and acircumferential face f1 and a vertical face g1 (in the drawing) formingthe step portion 221 of the inner stator and the circumferential face a4and the vertical face b4 forming the second step portion 774 of the rearframe 770 supportedly contact each other.

[0119] The armature 230 includes a magnet holder 231 having acylindrical form and a permanent magnet 232 coupled to the outercircumferential surface of the magnet holder 231. The armature 230 isinserted between the outer stator 210 and the inner stator 220.

[0120] The middle support member 760 of the frame unit 700 includes afirst step portion 762 formed at one side of the annular body 761 havinga predetermined thickness and width and a second step portion 763 formedat the other side thereof.

[0121] A circumferential face h3 forming the first step portion 762 anda circumferential face h4 forming the second step portion 763 make theconcentric circle, and the outer circumferential face of the annularbody 761 and the circumferential face h3 forming the first step portion762 make the concentric circle. The inner diameter of the annular body761 is larger than the inner diameter of the outer stator 210 of thereciprocating motor 200.

[0122] The middle support member 760 is insertedly coupled to the stepportion 212 of the outer stator of the reciprocating motor 200. At thistime, the circumferential face h3 and the vertical face k3 (in thedrawing) forming the first step portion 762 of the middle support member760 and a circumferential face d2 and a vertical face e2 forming thestep portion 212 of the outer stator 210 supportedly contact each other.

[0123] The front frame 750, which constructs the frame unit 700,includes a predetermined form of body part 751, a cylinder insertionhole 752 formed at the central portion of the body part 751, acylindrical interval maintaining part 753 having a predeterminedthickness and width and a step portion 754 formed at the end of theinterval maintaining part 753.

[0124] The step portion 754 is formed with a circumferential face m2having a predetermined with and a vertical face n2 (in the drawing)formed vertical to the circumferential face m2. The step portion 754 isformed by the corner of the interval maintaining part 753.

[0125] The step portion 754 of the front frame 750 is insertedlycombined with the second step portion 763 of the middle support member760.

[0126] At this time, the circumferential face m2 and the vertical facen2 forming the step portion 754 of the front frame 750 supportedlycontact a circumferential face hr and a horizontal face k4 forming thesecond step portion 763 of the middle support member 760, respectively.

[0127] The compression unit 300 includes a cylinder 310 and a piston320.

[0128] The cylinder 310 is inserted into the cylinder insertion hole 752of the front frame 750.

[0129] At this time, the inner diameter of the cylinder 310 and thecircumferential faces a3 and a4 of the first and the second stepportions 773 and 774 make the concentric circle, and the inner diameterof the cylinder 310 and circumferential faces h3 and h4 of first andsecond step portions 762 and 763 of the middle support member 760 makethe concentric circle.

[0130] The piston 320 includes a flange 322 extended and bent to have apredetermined area at one side of the body part 321 having a annular barform with a predetermined length in which a gas flowing passage (F) isformed in the longitudinal direction.

[0131] The body part 321 of the piston 320 is inserted into the cylinder310 and the flange 322 is coupled to the armature 230. At this time, thegas flowing passage (F) of the cylinder 310 and the through hole 772 ofthe rear frame 770 communicate each other.

[0132] An annular groove 311 having a predetermined width and depth isformed on the inner wall of the cylinder 310 of the compression unit300. The distance between the groove 311 and the front end of the headof the cylinder 310 is longer than the distance between the groove 311and the rear end of the cylinder 310.

[0133] The groove 311 of the cylinder is preferably formed to bepositioned roughly at the middle portion of the overall length of thepiston 320 when the piston 320 comes to the bottom dead point.

[0134] At least one lubricant through hole 312 is provided within thegroove 311 of the cylinder, having the smaller inner diameter than thewidth of the groove 311.

[0135] It is preferred that the lubricant through hole 312 is formedboth at the upper and the lower portions, so as to be positioned in thevertical line on the basis of the lubricant face.

[0136] The resonance spring unit 600 includes a plurality of coilsprings 620 and a spring support member 630 supporting the plurality ofcoil springs 620 along with the frame unit 700.

[0137] The spring support member 630 is formed with a predeterminedarea, including a support 631 supporting the coil spring 630 and acombining part 632 formed bent extended from the support 631.

[0138] The combining part 632 of the spring support member 630 iscombined with the flange 322 of the piston 320 or the magnet holder 231,and the support 632 is positioned between the front frame 750 and themiddle support member 760.

[0139] The plurality of coil springs 620 are combined between the springsupport member 630 and the front frame 750, and the plurality of springs620 are combined between the spring support member 630 and the middlesupport member 760.

[0140] It is preferred that the coil springs 620 combined between thespring support member 630 and the front frame 750 and the coil springs620 combined between the spring support member 630 and the middlesupport member 760 are the same in number.

[0141] A resonance spring support (R) is provided at the front frame750, the spring support member 630 and the middle support member 760where the coil springs 620 are positioned, to which one side of the coilsprings 620 is insertedly fixed.

[0142]FIG. 11 is a schematic view showing a position of a resonancespring support of the reciprocating compressor in accordance with thesecond embodiment of the present invention.

[0143] As shown in FIG. 11, the resonance spring supports (R) are formedequivalent to the number of the coil springs. And, the resonance springsupports (R) formed at the front frame 750, the middle support member760 and the spring support member 630 are stepped corresponding to theouter diameter of the coil spring 620.

[0144] The resonance spring support (R) are formed at equal intervalsand arranged symmetrical to the central axis of the middle supportmember 760.

[0145] That is, the plurality of coil springs 620 positioned between thefront frame 750 and the spring support member 630 and the plurality ofcoil springs 620 positioned between the middle support member 760 andthe spring support 630 are arranged in parallel so as not to bepositioned in the same central line, so that the eccentric force due toa torsion generated by the tensile contraction of the coil spring issolved.

[0146]FIG. 12 is a partial sectional view showing a windage lossreducing through hole of the reciprocating compressor in accordance withthe second embodiment of the present invention.

[0147] As shown in FIG. 12, a through hole r1 for reducing a windageloss is formed at the middle of the resonance spring support (R), andthe step faces r2 of each resonance spring support (R) of the middlesupport member 760 and the front frame 750 are all formed positioned onthe same plane.

[0148] A circle r3 connecting the central line of the plurality ofresonance spring supports (R) make the concentric circle with thecircumferential faces h3 and h4 forming the first and the second stepportions 762 and 763 of the middle support member 760.

[0149] Preferably, the middle support member 760, the front frame 750and the spring support member 630, where the resonance spring support(R) is formed, are made of a material having the same hardness as thatof the coil spring 620.

[0150] Preferably, the resonance spring support (R) is also made of amaterial having the same hardness as that of the coil spring 620.

[0151]FIG. 13 is a partial sectional view showing a support protrusionand an insertion recess formed at the spring support of thereciprocating compressor in accordance with the second embodiment of thepresent invention.

[0152] As shown in FIG. 13, the resonance spring support (R) includes asupport protrusion r4 protruded toward inner diameter of the coil spring620, and a circular insertion recess r5 formed around the supportprotrusion.

[0153] The support protrusion r4 may be fabricated as a separatecomponent and a through hole is formed at the middle support member 760and the front frame 750, so that the support protrusion may be forciblyinserted into the through hole and fixed therethrough. The through holer1 is formed at the central portion of the support protrusion r4.

[0154]FIG. 14 is a partial sectional view showing a construction of aninitial position control member of the reciprocating compressor inaccordance with the second embodiment of the present invention.

[0155] As shown in FIG. 14, an initial position control member 930 forcontrolling the initial position of the piston 320 of the compressionunit 300 is provided at the resonance spring support (R). The initialposition control member 930 is formed as an annular plate having apredetermined thickness.

[0156] When an initial position of the piston 320 which constructs thecompression unit 300 is set, the initial position of the piston 320 iscontrolled by inserting the initial position control member 930 having apredetermined thickness in the coil spring 620 and the spring support(R) fixedly supporting the coil spring 620.

[0157] The suction unit 400 includes a gas flowing passage (F) formed atthe through hole 772 of the rear frame 770, at the inner hole of theinner stator 220 of the reciprocating motor and inside the body part 321of the piston 320 and a suction valve 410 coupled to the front end ofthe piston 320, for opening and closing the gas flowing passage (F)according to the pressure difference.

[0158] The discharge unit 500 includes a discharge cover 510 combined tocover the cylinder 310, that is, the compression space (P), a dischargevalve 520 positioned inside the discharge cover 510, for opening andclosing the compression space (P) of the cylinder 310, and a valvespring 530 for elastically supporting the discharge valve 520.

[0159] The front frame 750, the middle support member 760 and the rearframe 770 which support the both sides of the reciprocating motor 200 isengaged by a plurality of engaging bolts and nuts each having apredetermined length.

[0160]FIG. 15 is a schematic view showing a bolt engaging part of thereciprocating compressor in accordance with the second embodiment of thepresent invention.

[0161] As shown in FIG. 15, when explained in view of the rear frame770, the bolt engaging portion 775 is extendedly protruded in asemi-circle form at the marginal portion of the body part 717 of therear frame, in which a screw hole is formed.

[0162] The plurality of bolt engaging portions 775 are disposed at theupper and the lower sides on the basis of a horizontal line when therear frame 770 is vertically positioned, and the bolt engaging portions775 are positioned at the left and the right sides on the basis of thecentral vertical line of the rear frame 770, that is, specifically, ofthe body part 771 of the rear frame 700.

[0163] The front frame 750 and the middle support member 760 may beengaged by an engaging unit, and the middle support member 760 and therear frame 770 may be engaged by a separate engaging unit.

[0164] A fillet portion (C) is formed at the corner portions of thefront frame 750, the rear frame 770 and the middle support member 760which construct the frame unit 700.

[0165] The fillet portion (C) includes a relatively large portion and arelatively small portion.

[0166] The fillet (C) may be modified to a flat form chamfer.

[0167] Since the front frame 750 constructing the frame unit 700 and thebolt engaging portion 715 engaging the middle support member 760 and therear frame 770 are positioned between the vertical line and thehorizontal line rather than being positioned on the central verticalline and the horizontal line of the frame unit 700, and the fillet (C)is provided at the corner of the frame unit 700, the frame unit 700 isprevented from contacting the inner face of the container 100 and thedistance to the inner face is minimized. Thus, its structure is compact.

[0168] The support spring 800 includes a plurality of coil springs. Oneside of the support spring 800 is fixedly supported at the bottom of thecontainer 100 and the other side thereof is fixedly supported by theframe unit 700.

[0169] The structure in which the support spring 800 and the frame unit700 are fixedly supported is the same as described with respect to thefirst embodiment.

[0170] As described in the first embodiment, a first connector 120having two power supply terminals 121 to which an external power issupplied and at least one fixing terminal 122 is formed at the container100.

[0171] A second connector 920 is provided having two power supplyterminals 921 connected to the power supply terminal 121 of the firstconnector 120 and withdrawn from the reciprocating motor 200 to supply apower to the reciprocating motor 200 and a fixing terminal 922insertedly combined with the fixing terminal 122 of the first connector.

[0172] The operation mechanism of the reciprocating compressor inaccordance with the second embodiment is similar to that of the firstembodiment.

[0173] In the reciprocating compressor of the second embodiment of thepresent invention, since the piston 320 is linearly and reciprocallymoved in the cylinder 310 upon receipt of the linear and reciprocaldriving force of the reciprocating motor 200, to compress the gas, thereciprocating compressor is stably driven.

[0174] In addition, since the stroke of the piston 320 can be controlledby controlling the linear movement distance of the reciprocating motor200, the amount of the compressed gas to be discharged can be accuratelycontrolled.

[0175] The step portion 211 of the outer stator 210 which constructs thereciprocating motor 200 supportedly contacts to be combined with thefirst step portion 773 of the rear frame 770 which constructs the frameunit 700, and the step portion 221 of the inner stator 220 of thereciprocating motor 200 supportedly contacts to be combined with thesecond step portion 774 of the front frame 770, so that theconcentricity of the outer stator 210 and the inner stator 220 can beaccurately adjusted and the interval therebetween can be constantlymaintained.

[0176] In addition, the first step portion 762 of the middle supportmember 760 of the frame unit 700 supportedly contacts to be combinedwith the other step portion 212 of the outer stator 210 of thereciprocating motor, so that the assembly state is firm.

[0177] The components constructing the frame unit 700, the reciprocatingmotor 200 and the compression unit 300 are combined by being contactedand supported by the step portions forming the concentric circle, sothat the assembly tolerance is minimized and the assembly working iseasy.

[0178] Moreover, since the rear frame 770 of the frame unit 700 supportsboth the outer stator 210 and the inner stator 220 of the reciprocatingmotor 200 and the middle support member 760 supports only the outerstator 210, a leakage of flux formed at the outer stator 210 and theinner stator 220 can be reduced.

[0179] As so far described, the reciprocating compressor of the presentinvention has many advantages.

[0180] For example, first, since the stable driving is made in itsoperating, generation of a vibration and a noise can be minimized,heightening a reliability.

[0181] Secondly, since the gas discharge amount according to the strokecontrol can be accurately controlled, an unnecessary loss can bereduced.

[0182] Thirdly, the assembly tolerance of the components can beminimized, the assembly working is easy, and thus, the compressionperformance is heightened and assembly productivity can be improved.

[0183] It will be apparent to those skilled in the art that variousmodifications and variations can be made in the plasma polymerization onthe surface of the material of the present invention without departingfrom the spirit or scope of the invention. Thus, it is intended that thepresent invention cover modifications and variations of this inventionprovided they come within the scope of the appended claims and theirequivalents.

1. A reciprocating compressor comprising: a container communicating witha gas suction pipe for sucking a gas; a reciprocating motor installed inthe container and having an outer stator and an inner stator providedwith at least one step portion at both sides thereof, and an armaturelinearly moving therebetween; a compression unit having a cylinder and apiston inserted in the cylinder to receive a linear and reciprocaldriving force of the reciprocating motor and compress a gas while makinga linear and reciprocal movement; a suction unit sucking a gas suckedinto the container through the gas suction pipe due to a pressuredifference in the compression unit, into the compression unit; adischarge unit discharging the gas compressed in the compression unit tooutside the container; a resonance spring unit elastically supportingthe piston and the armature; and a frame unit supporting the compressionunit and the reciprocating motor and having a front frame which supportsthe reciprocating motor at the front side and a rear frame whichsupports the reciprocating motor at the rear side, one of the front andthe rear frame having at least two step portions for supporting bothouter stator and inner stator of the reciprocating motor, the frontframe and the rear frame having at least one step portion of whichcircumferential face forms a concentric circle with the inner diameterof the cylinder.
 2. The compressor of claim 1, wherein a middle supportmember is inserted between one of the front frame and the rear frame andthe reciprocating motor, to support the reciprocating motor together. 3.The compressor of claim 2, wherein a step portion is formed at bothsides of the middle support member, one of which supportedly contactsstep portions of the reciprocating motor and the other of whichsupportedly contacts step portions of the frame.
 4. The compressor ofclaim 3, wherein circumferential faces of the step portion formed atboth sides of the middle support member make a concentric circle.
 5. Thecompressor of claim 2, wherein the middle support member is formed in acircle and has at least one step circumferential face making aconcentric circle with its outer circumferenctial surface, so that theouter circumferential surface supportedly contacts the step portions ofthe motor and the step portions of the frame.
 6. The compressor of claim2, wherein a through hole having a predetermined diameter is formed atthe center of the middle support member, of which the inner diameter isgreater than the inner diameter of the outer stator of the reciprocatingmotor.
 7. The compressor of claim 2, wherein the middle support memberincludes at least one resonance spring support formed with a stepportion corresponding to the outer diameter of the coil spring, so as tosupport the circular coil spring which constructs the resonance springunit.
 8. The compressor of claim 7, wherein the resonance springsupports are formed at equal intervals.
 9. The compressor of claim 7,wherein the resonance spring supports are arranged symmetrical to thecentral axis of the middle support member.
 10. The compressor of claim7, wherein the middle support member or the spring support is made of amaterial having the same hardness as that of the coil spring of theresonance spring unit.
 11. The compressor of claim 7, wherein each stepface of the step portions is formed on the same plane.
 12. Thecompressor of claim 7, wherein a circle connecting the central lines ofthe plurality of resonance spring supports makes the concentric circlewith the circumferential face forming the step portions of the middlesupport member.
 13. The compressor of claim 7, wherein the resonancespring support includes a support protrusion protruded toward the innerdiameter of the coil spring.
 14. The compressor of claim 13, wherein acircular insertion recess is formed at the contact line where the outercircumference of the support protrusion and the face of the middlesupport member are met.
 15. The compressor of claim 7, wherein a throughhole is formed at the resonance spring support.
 16. The compressor ofclaim 15, wherein the support protrusion is fixedly inserted into thethrough hole.
 17. The compressor of claim 16, wherein a through hole isformed at the inner side of the support protrusion.
 18. The compressorof claim 7, wherein an initial position control member for controllingan initial position of the piston of the compression unit is provided atthe resonance spring support.
 19. The compressor of claim 18, whereinthe initial position control member is formed in an annular plate with apredetermined thickness.
 20. The compressor of claim 1, wherein theframe unit further includes an inner support member for supporting theinner circumferential wall of the inner stator of the reciprocatingmotor.
 21. The compressor of claim 2 or 20, wherein the circumferentialface of the step portion of the middle support member and the outerdiameter of the inner support member make a concentric circle.
 22. Thecompressor of claim 20, wherein a stopper for supporting the stepportion of the inner stator is provided at the end of the inner supportmember so that the inner stator may not be pushed in the movementdirection of the piston.
 23. The compressor of claim 20, wherein theinner support member is integrally combined with the inner stator bywelding or bolting.
 24. The compressor of claim 1, wherein a fillethaving a curved surface or a flat surface is formed at the corners ofthe front frame and the rear frame of the frame unit.
 25. The compressorof claim 24, wherein the fillet includes a portion with a relativelywide width and a portion with a relatively narrow width.
 26. Thecompressor of claim 1, wherein a support spring for supportingcomponents positioned inside the container is provided at the bottom ofthe container, of which one side is supported at the bottom of thecontainer and the other is supported by the frame unit.
 27. Thecompressor of claim 26, wherein a combining protrusion for supportingthe support spring is provided at the frame unit, the combiningprotrusion being integrally formed with the frame unit.
 28. Thecompressor of claim 27, wherein an insertion recess is formed at acontact line where the outer circumference of the combining protrusionand the frame unit met.
 29. The compressor of claim 1, wherein aplurality of bolt engaging portions are formed at the marginal portionsof the frame unit, the bolt engaging portions being arranged at theupper and the lower sides on the basis of a horizontal line when theframe is vertically positioned.
 30. The compressor of claim 29, whereinthe bolt engaging portions are arranged at the left and right sides onthe basis of the central vertical line of the frame unit.
 31. Thecompressor of claim 1, wherein an annular groove with a predeterminedwidth and depth is formed at the inner wall of the cylinder of thecompression unit, and the distance between the groove and the front endof the head of the cylinder is greater than the distance between thegroove and the rear end of the cylinder.
 32. The compressor of claim 31,wherein the groove of the cylinder is roughly positioned at the middleportion of the overall length of the piston when the piston ispositioned at the bottom dead point.
 33. The compressor of claim 31,wherein at least one lubricant through hole with a smaller innerdiameter than the width of the groove is formed in the groove of thecylinder.
 34. The compressor of claim 33, wherein the lubricant throughholes are formed positioned at the upper and the lower sides on thevertical line on the basis of the lubricant face.
 35. The compressor ofclaim 1, wherein a mass member is provided at the flange of the pistonwhich makes a linear reciprocating movement upon receipt of the drivingforce from the reciprocating motor and to which the armature of thereciprocating motor is combined.
 36. The compressor of claim 35, whereinthe mass member has a disk form with a predetermined thickness.
 37. Thecompressor of claim 1, wherein the piston which makes a linearreciprocating movement upon receipt of the driving force from thereciprocating motor and the armature of the reciprocating motor areengaged by sequentially arranging the flange of the piston, the plasticarmature and a resonance spring base supporting the resonance springunit.
 38. The compressor of claim 1, wherein a first connector havingtwo power supply terminals to which an external power is supplied and asingle fixing terminal is provided at one side of the container, and asecond connector is provided having two power supply terminals comingout from the reciprocating motor so as to be connected with the powersupply terminal of the first connector and supply a power to thereciprocating motor and a second connector having a fixing terminalinsertedly combined with the fixing terminal of the first connector. 39.The compressor of claim 1, wherein at least one step portion with asmaller outer diameter than the outer circumference adjacent to thereciprocating motor of the rear frame is provided at the rear frame ofthe frame unit.